1. Field of the Invention
The invention relates to a semiconductor structure, and in particular to a pixel structure and a method for fabricating the same.
2. Description of the Related Art
In liquid crystal display fabrication, the aperture ratio of pixels affects utilization of backlight and panel brightness. The aperture ratio is determined by the interval between the conductive electrode and data line. However, the capacitance between pixel and data line (Cpd) may increase when the interval is small, resulting in crosstalk.
To reduce capacitance between pixel and data line (Cpd), methods can include, for example, increasing storage capacitance to reduce the ratio of Cpd in total capacitance of a sub-pixel, disposing a stable electric shield between the pixel electrode and data line to reduce the parasitic capacitance therebetween, and utilizing an organic low-k insulation film (K=2.7˜3.5) formed by the photo-imaged or spin on glass (SOG) methods provided by Optical Imaging Systems (OIS) to reduce the capacitance between pixel and data line.
However, increasing the area of the storage capacitor may reduce the aperture ratio. Also, the organic low-k insulation film with strong water adsorption, yellowing, and low interface adhesion may affect yield and throughput.
FIG. 1A is a top view of a conventional pixel structure. FIG. 1B is a cross sectional view taken along A-B line of FIG. 1A. A pixel structure 1 comprises two insulation layers such as a gate insulation layer 2 and a passivation layer 3, and two metal layers. One of the metal layers is fabricated to form a gate line 4 and a common line 5. Another metal layer is fabricated to form a data line 6 and a source/drain 7. In the structure, the parasitic capacitance between the data line 6 and the pixel electrode 8 can be reduced due to a proper interval therebetween. A large black matrix, however, is required to sufficiently shield the light leak region, thus decreasing the aperture ratio.